IBob

Moneybox, I have just been advised that the filters you see there are no longer to be used. So, I'll be getting onto that. The hose is the correct size, as I recall, for the splitter and the carb spigots. I can't tell you offhand what size it is. I can tell you that I did the original flow testing via them, and it was very much more than adequate.

bobcharl, the flexible SS radiator 'hoses' work fine. My kit was despatched Dec 2014 with them ,and so far as I know they are still supplying them: if there was a problem I'm pretty sure we would have heard by now. To avoid chafing, it's not difficult to secure them with cable ties, threaded through a short 'bead of regular hose to space them from the securing point. And they have the advantage that you can work quite a tight bend into them without flattening or collapse, as regular hose does when bent tightly. So makes for a very neat compact installation. You still need regular hose and hoseclips to make the junction at the ends.

Aro, I can have no idea. What I was trying to suggest, in a broader sense, is that there might be some benefit in stressing certain parts of certain procedures.......and focusing on why. For instance, the standard overhead rejoin, as taught here, is well documented with minimum heights and positions over the airfield. But so far as I know, the reasoning behind that is not explained. Sure, most pilots will hopefully eventually figure out the why around all that........but why not tell them in the first place?

I think the ADS-B is a side issue: flying in that situation you would want your eyes mostly outside. And from what we have so far, it looks as though the helo may have transitioned fromapprox 200 to approx 300 late in the piece. I have wondered whether flight training would benefit from some deliberate focus on potential high risk collision points, explaining them to the student. For instance, some years ago I was almost taken out by someone wrongly located and a bit low while doing a standard overhead rejoin. I was taking off. So in that instance the risk was at the crossover point between traffic taking off and traffic crossing the strip. Had that risk been emphasised in training, we would all be aware of the need to cross with adequate height, and in an appropriate place. Similarly, I have learnt to be wary of crossing the flight path of potential outgoing traffic for many miles out, where they may still be in a hard climb, in our case in line with the strip due to it's orientation. And a third example: a very good look downwind on the base leg and before turning final. Twice I have seen aircraft coming straight in cross in front of traffic on late base leg, and both times in complete radio silence. Eventually (hopefully) we may work all these things out for ourselves. But why not point them out during training? And while it's easy to be smart after the event......if the standard helo briefing had included 'under no circumstances exceed the maximum height, doing so will bring you directly into the path of airport traffic'..........maybe all those folk would still be walking around today.

When something like this happens, there is always some discussion and conjecture. I would suggest that is human enough, and in most cases not because anyone is seeking 'likes'. And no-one is obliged to take part in any of that if they prefer not to. As fort the 'real experts', I don't know how it goes in the US, but certainly in this part of the world, history has shown they are not as all-seeing as one would wish. And the idea of us all sitting silent until they have spoken is a bit odd. In my view.

So, Deano, your principal concerns with the commentary are: 1. Assumptions as to who was flying what, and who was Captain at the time. 2. Assumptions about what sort of military flight it was, and for whose benefit. 3. Your personal belief that it is unlikely they were using NVG. ????

Specifically???

They've been working on this for 9 years. The fact that they can 'only' get a 1% reduction in drag seems to indicate that the thing was pretty well optimised to start with?

I guess, the way they are angled, the vanes will act to lift the tail. Though why that should induce less drag than lifting it with elevator trim, I don't know. Another possibility is that the modified airflow serves to reduce the 'downwards lift' of that rear section. Perhaps they disrupt the laminar flow, so causing that downward lift (or part of it) to stall?

Them's pretty big vanes at 4" x 16". Be interesting to see the detail of how they reduce drag, which the article says is the result of the upswept loading door/s shape.

KJ, if you watch the briefing, they are very specific about what they have so far in terms of altitudes. In fact they go through it about 3 times: for the Blackhawk at time of briefing, they only have ATC radar derived altitude. These choppers are part of a continuity of government arrangement, for moving government personnel out if the seat of government is threatened in some way. In those circumstances, they definitely wouldn't want to be transmitting their location by ADS-B or any other means. So maybe they run dark on these exercises???

Yes, I just saw their NTSB press briefing. While no doubt they have a long way to go, they sound fairly confident of the 325' figure at this point, derived from corrected ADS-B and another source that I didn't catch. For the helo, so far they have only the ATC radar readout, which they say shows 200', albeit a less granular (precise) source. This is understandably causing some press confusion, despite them going over it several times. I also watched commentary from another pilot who pointed out that in the necessary low level banked left turn for a landing on the shorter 33 strip, the airline pilots would have been tightly focused to the left then ahead............with the helo meanwhile coming from the right.

Deano, the Blancolirio summary I watched had the Helo at 200'..........then 300' just before the collision. I don't know how those numbers were derived. I guess we'll find out in due course. Or not.......( One of the reports right after the event contained the assertion that the airliner 'suffered a sudden loss of altitude passing over the river', or words to that effect. Where that came from, and whether it was just uninformed conjecture, I don't know. Either...

How was the Helo altitude derived? And does/did that value require correction for QNH?

You mean the gentleman's aerial carriage, Nev?........)

This is how ICP present it for the Savannah, facthunter: a graph with 2 lines showing the forward and rear limits. Using the 'arms' provided and the weights (for fuel, people and baggage) you combine the results with the original aircraft w & b figures, then plot the result on the graph to see where you are on the allowable range for that all-up weight. That part is very straightforward (and it's also near impossible to load outside the limits unless you were to grossly overload the baggage, which has a limit of 20Kg.)

Thanks all for your input.....I'm learning! I see now that there is no fixed centre of lift, and that a forward datum avoids possible errors with negative values. What brought this up is the question of weight in the baggage area (immediately behind me) vs weight in a tail locker. In a steady flight situation, a much smaller weight in the tail locker will have a similar balance effect as a larger weight in the baggage area. But how much smaller? Measuring from the LE as the POH does, the tail locker 'arm' would be approx 3.35M. As previously stated, the baggage area 'arm' is 1.32M. This suggests that 10Kg in the baggage area has the same w & b effect as almost 4Kg in the tail locker. That just doesn't feel right, somehow.............(

My Savannah (no sweep on the wings) came with a set of standard 'arms' in metres for use when calculating W & B for a given load. Eg for baggage area: Kg baggage X 1.32M, 1.32 being the given 'arm' for baggage. These arms all appear to be measured from the leading edge of the wing. I would have thought they should be measured from the centre of lift. As any weight forward of that would push the nose down and vice versa. I'm interested as I've been thinking about the difference of weight in baggage vs weight in tail, and with the given arm for baggage, the (theoretical) difference does not seem as great as I would have expected. Can anyone explain this (why the leading edge?) to me.....or point me to a thread that will do that?

My tank seepage was a bit scary: No signs of it during initial ground runs or test flights. But shortly after someone said I had a damp patch under, and when I popped the belly hatch the entire outer walls of the tank were damp and shiny: fuel making it's way down the outside. And quite probably an explosive fuel/air mixture in the confined space of the rear fuselage.............(

Moneybox, as I recall the fittings in my tank are as you describe: threaded brass 'nuts', moulded in.

As I recall, the two main ports were threaded females that looked to be moulded into the tank, and the fittings that went into them had some sort of 'rubber' ring to make the seal. I wonder how that third port was fitted to make it fuel-tight? My tank developed seepage from from one of those tops ports, which wasn't evident initially. I had to pull the tank and trim some of the plastic round the fitting to get it to seal properly. May be worth keeping an eye on initially, Marty.

I was wondering that too: the standard ICP unit comes with just 2 ports (plus the level switch) in the top, so far as I know. The VG model I have seen was built with each of those ports connected to one of the two wing tanks. To give venting they then brought both/all tanks into one port, and used the other for the vent line.

Marty, at cruise, if I valve off all fuel to the receiver, the low fuel indicator comes on after 2.5minutes. That's about 0.7L. Which is to say it takes a fair sized bubble to give false alarms. But I have seen it in an unvented VG.

Ops....certainly not got him! Got the message....and added the method he outlined to my quite narrow fund of knowledge. Thanks, Blue.

Gotcha............)